The present invention relates generally to a process for producing IC (integrated circuit) cards. More particularly, the present invention relates to a process for producing cards, which can avoid exposure, on the card surface, of unevennesses of components such as IC chips, capacitors and antenna coils mounted or formed on a mount substrate.
In conformity with the rapid progress of electronic application technology, thin high-performance IC cards with large storage capacity are now increasingly employed for instantaneously carrying out inputs and outputs for information storage and processing with external memory units in the field of personal recognition, management of bank deposits, examination of railway tickets, supervision at expressway tollbooths, etc. Among various IC cards, especially, noncontact-type IC cards enable performing information inputs and outputs through wave transmission and reception even at a given distance without the need to carry out time-consuming operation, such as card insertion in a reader installed on an external processor side, for information input and output as different from conventional contac-type IC cards. Therefore, contactless type IC cards are now becoming mainstream because of excellent operation efficiency, accuracy in information input and output and extremely high information processing speed.
Common IC cards are obtained by first overlaying one surface of a substrate of a synthetic resin film such as a film of polyethylene terephthalate with circuits with the use of a copper foil, a silver paste or the like, subsequently superimposing IC chips, capacitors, antenna coils, etc. on the circuits, and covering the circuit side of the substrate with a laminate film having on its one side a heat sensitive or pressure sensitive adhesive layer.
However, these IC cards have a drawback in that unevennesses of components such as IC chips and capacitors are exposed on the laminate film.
Thus, IC cards of the following structure intended to minimize component unevennesses on the cards have been developed.
The IC cards 120, as shown in FIG. 6, fundamentally, comprise a mount substrate 12 of a synthetic resin film 100 such as a film of polyethylene terephthalate, and transmission/reception coils 102 for transmitting and receiving input/output wave signals and capacitors 104 on the surface of the mount substrate 12. The mount substrate 12 has device holes 114 wherein integrated circuits (IC chips) 106, such as semiconductor memory, for information storage and processing are fitted. Copper foil circuits 108 for wiring provided to form circuits between components are stuck to the mount substrate 12 through an adhesive layer 112. Both surface sides of the mount substrate 12 are overlaid, by hot laminating, with laminate films 110 having a thermal adhesive layer 109.
However, with respect to the IC cards of this structure, there still remains the problem that unevennesses of components such as transmission/reception coils 102, capacitors 104, IC chips 106 and copper foil circuits 108 for wiring are exposed on the surfaces of the laminate films 110. Therefore, in the event of printing a company name or other information on a card surface, it is difficult to use conventional printers. Special printers such as an ink jet printer must be employed.
Further, in the event that unevennesses of, for example, IC chips are exposed on IC card surfaces, there is such a danger that IC chips and other components are damaged by impact on the unevennesses when the IC cards are placed in a bag or the like and carried. As a result, reading of read information cannot be performed.
Still further, it is needed to disenable recognition of the presence of components such as IC chips in the IC cards for the purpose of prohibiting alteration of information stored in the IC cards.
In these circumstances, it is an object of the present invention to provide a process for producing cards, which can avoid exposure, on card surface, of ,unevennesses of components such as IC chips, capacitors and antenna coils mounted or formed on a mount substrate.
The present invention has been made with a view toward attainment of the above problems and object. The process for producing cards according to the present invention comprises the steps of:
continuously feeding a mount substrate and simultaneously feeding a pair of sheet members on both surface sides of the mount substrate in such a manner that the mount substrate is interposed between the pair of sheet members;
feeding an adhesive in fluid condition between each of the surfaces of the mount substrate and the sheet member opposite thereto; and
regulating a distance between the pair of sheet members into a constant spacing and hardening the adhesive.
By virtue of this process, the unevennesses of components, such as IC chips, capacitors and antenna coils, mounted or formed on a mount substrate are absorbed by the adhesive in fluid condition, and their exposure on the card surfaces can be avoided.
Therefore, a company name or other information can be printed on a card surface by the use of conventional printers without the need to employ special printers such as an ink jet printer. Further, even when the IC cards are placed in a bag or the like and carried, no impact would be exerted on components such as IC chips. Thus, the components are protected, and damaging of the IC cards can be avoided. Still further, the presence of components such as IC chips in the IC cards cannot be recognized from outside, so that alteration of information stored in the IC cards can be prevented.
In the process for producing cards according to the present invention, one of the pair of sheet members preferably consists of a release sheet.
As a result, an adhesive layer can be exposed by stripping the release sheet from the produced IC cards, and the IC cards can be stuck to, for example, a surface of corrugated cardboard box through the exposed adhesive layer as contactless-type IC labels. Thus, the IC cards can be utilized in the information management for physical distribution system and the like.
Moreover, with respect to the process for producing cards according to the present invention, it is preferred that at least one of the pair of sheet members consist of a release sheet, and that the process further comprise the steps of stripping the release sheet from the mount substrate after the hardening of the adhesive; and sticking a laminate sheet member onto adhesive layer surface exposed as a result of the stripping of the release sheet.
In this process, an adhesive layer can be formed on a surface of mount substrate in advance by the use of release sheet, and thereafter a laminate sheet member suitable for laminating can be stuck thereby to the mount substrate.